The quest for more efficient machines is always ongoing in the engineering world. This project is no different. ABB are investigating a new type of propeller that seems to offer increased efficiency compared to normal screw propellers. That is a so called foil wheel propeller. The foil move in a circular pattern with the fluid stream moving in the radial direction of the propeller instead of the axial as in a screw propeller. If the propeller is placed and modeled correctly it can also be used as a thrust vectoring device. This report focuses on the fluid physics of the foil wheel propeller, or as it is called in this report radial flow propeller. First of all the movements and interactions of the blades must be understood. Both to keep the efficiency high to compete with screw propellers, but also to foresee any problems that may occur with such a new device. A scaled down version of the propeller have been commissioned by ABB and will be tested in some time after the work within this report is completed. The effects associated to this will also be analyzed. The tool to compute the flow physics of the radial flow propeller will be computational fluid dynamics. Computational fluid dynamics uses a numerical method to compute the entire fluid field in space and time. The flow around the propeller is highly complex so a detailed analysis is needed if a well functioning control system is to be constructed for instance. The differences between the downscale and the full-scale are great, even when the non dimensional coefficients are considered. The down-scale case will be less efficient, it will be difficulties predicting the performance of the full-scale since the downscale flow is much less powerful than the full-scale case. The interaction between the blades has a large effect. There is a strong relation between angle of attack and the number of blades. The forces that are large change by about 30\% so it must definitely be considered if a model is to be used for a control system.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:liu-144535 |
| Date | January 2017 |
| Creators | Thelin, Fredrik |
| Publisher | Linköpings universitet, Mekanisk värmeteori och strömningslära |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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